Dynamoelectric machines, such as, for example, three phase motors, are generally manufactured, in some sizes, with each phase winding of the motor stator divided into two equal size coils. The ends of each of these coils are brought out to a junction box where they are accessible for connection. Since such a motor has three phase windings, and each winding is divided into two coils, there are twelve leads brought to the junction box. The twelve leads may be connected in several different combinations in order to electrically configure the motor both into a selected type and for operation at a predetermined terminal voltage. For example, if the coils of each of the windings are connected in an electrical series circuit, the motor can be operated at twice the terminal voltage, e.g., 440 volts, as would be possible if the coils of each of the windings are connected in an electrically parallel configuration. leads, the motor windings can be electrically connected into a Wye or a delta configuration.
Because there are so many different combinations of connections of the twelve lead wires and because an error in connecting even one of the lead wires could result in destruction of the dynamoelectric machine, various types of connector or terminal blocks have been devised for terminating the coil lead wires in preselected orientations. Some of these connector blocks utilize bulky, complicated tap-changing rotary switches which, in addition to the disadvantage of large size, are generally expensive. Other forms of connector blocks have been developed in which the coil lead wires are soldered or otherwise substantially permanently attached to a base plate and a plug having preselected jumpered terminals adapted to mate with the base plate effects the interconnection of the lead wires. It is believed that at least one disadvantage of the prior connector blocks has been the manner in which the lead wires are connected. In particular, connections of which this inventor is aware are believed to require excess lead wire length. Furthermore, replacement of a damaged termainal in such systems is believed to possibly require replacement of the entire base plate.